Narrow portion of the terminal choledochus is a cause of upstream biliary dilatation in patients with anomalous union of the pancreatic and biliary ducts

Figure 2 Endoscopic retrograde cholangiopancreatogram in a 21-year-old woman with AUPBD and cystic biliary dilatation (A). Diagram of the cholangiopancreatogram (B). The minimum diameter of the narrow portion of the terminal choledochus is 1.5 mm, and the maximum diameter of the upstream choledochus is 57 mm. Proximal dilatation of the MPD is also seen. AUPBD: anomalous union of the pancreatic and biliary ducts; NDS: narrow distal segment; P-B ductal union: pancreaticobiliary ductal union; narrow portion: narrow portion of the terminal choledochus; GB: gallbladder; MPD: main pancreatic duct.